An acousto-optic modulator (AOM) includes a transducer and an acousto-optic material. The transducer receives an electrical signal and converts the electrical signal into an acoustic wave that propagates in the acousto-optic material. Light incident on the acoustic-optic material is diffracted by the periodic index of refraction modulation that occurs while the acoustic wave propagates in the acousto-optic material.
An AOM may be used in an extreme ultraviolet (EUV) light source to, for example, deflect stray light from a beam path in a certain direction (for example, into another beam path and/or into a beam dump) and/or at certain times. To deflect light using the AOM, an acoustic wave having a constant frequency as a function of time may be injected into an acousto-optic material of the AOM. The AOM may be computer controlled, for example, the AOM may be controlled by a process stored in an electronic memory as executable instructions, the instructions being capable of executing on one or more electronic processors.
EUV light includes, for example, electromagnetic radiation having wavelengths of around 50 nm or less (also sometimes referred to as soft x-rays), including light at a wavelength of about 13 nm. EUV light may be used in a photolithography processes to produce extremely small features in substrates, for example, silicon wafers.